Action Statement FloraFlora and and Fauna Fauna Guarantee Guarantee Act Act 1988 1988 No. No. ### 106
Description and Distribution The Golden Sun Moth Synemon plana is a small diurnal moth belonging to the family Castniidae in the insect order Lepidoptera. The Castniidae includes 30 genera with representatives in the Neo- tropical, Oriental and Australian regions, indicating a Gondwanan origin. The Australian species are represented by a single endemic genus (Synemon) which contains about 43 species. The adults of all the species are generally dull-coloured; females have brighter hind wings.
Golden Sun Moth adults are unique among Synemon species for having semi-flightless females and exhibiting a high degree of sexual dimorphism. Golden Sun Moth Synemon plana The forewings of the male are dark brown with (Female bottom left, male top right) grey scales and the hindwings are bronzy-brown (illustration by Sarah Reglar from ACT Government and black. The underside of the male is pale grey (1998)) with brown patches. The forewings of the female are brown and grey, and the hindwings are bright orange with black submarginal spots. The underside of both wings of the female is white with black submarginal spots. The male has a wingspan of about 3.5cm whilst the female is smaller with a wingspan of about 3cm. Coloured illustrations of adults may be found in Common (1990) and in Dear (1997). No detailed descriptions or illustrations of the pupa and larva are known.
At the time of European settlement, the Golden Sun Moth was widespread and relatively continuous throughout its range, inhabiting grassy open-woodlands and grasslands (Edwards 1993). Distribution in Victoria Historical records show that the Golden Sun Moth (+ before 1970, 1970 onwards) was found as far north as Winburndale near (source: Atlas of Victorian Wildlife, NRE 1998) Bathurst and the Yass Plains in New South Wales (Edwards 1991; Venn 1993). In Victoria the Golden urban development, cultivation, weed invasion, Sun Moth once inhabited vast areas around wetland drainage, fertiliser application, Bendigo, Williamstown, Mansfield, Eildon, Salisbury overgrazing and changes in fire management have and Nhill. Bordertown was the only record in resulted in the decline of native grasslands, and South Australia (CNR 1995). It also occupied large the consequent loss of their associated areas of the Australian Capital Territory (Edwards invertebrate fauna. Habitat loss or alteration is 1991). The Golden Sun Moth is currently known considered to be the major cause of decline of from 10-12 sites in the ACT, and 29 sites in New many species of invertebrates. South Wales (Clark & O’Dwyer 1998). No Other factors which directly threaten the habitat, populations of the Golden Sun Moth have been and hence the viability of known populations, found recently in South Australia (Edwards 1994). include degradation of the habitat through rubbish In Victoria, the Golden Sun Moth is found in five to dumping and the inappropriate planting of trees. seven sites (NRE 1998). These sites are small and The Golden Sun Moth has a very specialised habitat isolated. A colony is found in the Salisbury of grasslands dominated by Austrodanthonia spp. Bushland Reserve (east of Nhill). The reserve, These grasslands have been almost entirely bounded by the Western Highway, a dirt road and destroyed, or significantly altered, by agriculture. private properties, is approximately 500 x 500m. Populations have been isolated and fragmented, However, it is thought that the Golden Sun Moth impeding the ability of the relatively immobile occupies only small areas of grassland within the females to recolonise areas, thereby reducing the reserve. Specimens have also been located along likelihood of genetic exchange. the railway line extending from Salisbury into Nhill (C. Crouch pers. comm.). A further site located at There is no evidence that predation by natural or Nhill is within the township on a small private introduced predators has contributed to the allotment. Another colony is located on the north- decline in the Golden Sun Moth. However, Willie east side of Mount Piper, south west of Broadford Wagtails Rhipidura leucophrys and robber flies in central Victoria. Populations have also been (family Asilidae) have been observed capturing the recorded north of Tallarook (80km north of Golden Sun Moth (New, O’Dwyer pers.obs.). Melbourne) and on the summit of Junction Hill on In its final recommendation the Scientific Advisory Yea Spur, north-east of Flowerdale (Douglas 1993). Committee (SAC 1994) determined that the Golden It is not known how large or extensive these Sun Moth is: colonies are and whether they still persist. The Golden Sun Moth was more recently found on a • in a demonstrable state of decline which is private grazing property near Dunkeld (Dear 1996), likely to result in extinction. a roadside verge in Hexham and at the Hamilton • significantly prone to future threats which are Community Parkland (New pers. comm.). likely to result in extinction. Current conservation Status • very rare in terms of distribution or abundance. The Golden Sun Moth has been listed as a Major Conservation Objective threatened taxon under the Flora and Fauna The major conservation objective is to ensure the Guarantee Act 1988. It is listed as endangered protection and conservation of existing known under the ACT Nature Conservation Act 1980 and populations of the Golden Sun Moth. This will be the NSW Threatened Species Conservation Act achieved by: 1995. • maintaining in the wild the seven extant Reasons for conservation status colonies with greater than 500 individuals to retain maximum genetic variation; The Golden Sun Moth has been eliminated over much of its former range. There are approximately • increase the number of known populations; 30 localities represented by museum specimens • maximising grassland habitat at all seven although only seven extant sites are currently sites through regenerating Austrodanthonia known The Golden Sun Moth is threatened by spp. and rehabilitating the sites; habitat loss, disturbance and fragmentation. • protecting and enhancing suitable natural Habitat degradation has resulted in local habitat areas to ensure that the percentage extinctions throughout its range. The major cause cover of Austrodanthonia is greater than of decline has been the loss of habitat because of forty percent. agricultural expansion and urbanisation. This decline has largely been caused by the loss of suitable food plants or by changes in the structure of grasslands. The widespread replacement of native vegetation with pasture plants and changes in vegetation composition and structure due to
2 Management Issues cultivation and weed invasion and are under continual threat from fertiliser application, altered Ecological Issues Specific to Taxon fire and grazing regimes. Remnants of native Habitat grassland and grassy woodland are limited in area and are fragmented. However, the importance of The Golden Sun Moth occurs in native grasslands these remnants to conservation is extremely high. dominated by species from the genus The Golden Sun Moth, having a specific habitat Austrodanthonia, in particular, Austrodanthonia relationship and dependence upon the host plant carphoides, A. auriculata, A. eriantha, and A. of Austrodanthonia spp. in native grasslands and setacea. These plants are found on a range of soil grassy woodlands, highlights the vital importance types in a variety of environmental conditions. of retaining the habitat. The alteration of However, the percentage cover of Austrodanthonia ecological processes and function within and must be greater than 40% to be suitable for the adjacent to remaining habitat of the Golden Sun Golden Sun Moth (Dear 1997). Moth is a threat to all remaining populations of the Life cycle species. Little is known about the reproductive life cycle of The Golden Sun Moth has been eliminated over The Golden Sun Moth, although it is likely that it much of its former range, and the remaining takes 2-3 years, as for other Castiinids (Edwards populations have been isolated thereby reducing 1994). The life history of Synemon magnifica has the likelihood of genetic exchange. Inbreeding may been described and it is suspected that the life lead to the accumulation and expression of history of the Golden Sun Moth is similar (Edwards deleterious genes and eventual population pers. comm.). In general female sun moths emerge collapse. from the pupa with fully developed eggs, ready to Populations are typically disjunct and are mate. After mating, the female deposits the eggs restricted to small, isolated remnants of native singly between the tillers of the food plant, and the vegetation within larger modified areas. soil, where they hatch in about 21 days. Although Golden Sun Moth females can fly, they tend to lay Females have reduced hind wings and are reluctant in wait, flashing their small bright orange wings to to fly even when disturbed, and whilst adult males attract the attention of patrolling males (Harwood are capable of active and prolonged flight they will et al. 1995). Ovipositioning in the species has not not fly long distances. Thus areas of suitable been observed. habitat are unlikely to be (re) colonised due to their poor dispersal ability. It is suspected that the first instar larvae tunnels into the tillers of the plant, feeding internally on Use of pesticides in pasture management, often in the plant tissue for about eleven months. The association with fertilisers, is likely to pose a direct number of larval instars is unknown. The larvae threat to the Golden Sun Moth since pesticides are construct short, silk-lined tunnels into the soil to used to control the larvae (and sometimes the feed externally on the rhizomes and roots, adults) of some Lepidoptera, Coleoptera and branching off along the rhizomes, thus developing Orthoptera pest species (army worms, cut worms a tunnel system. Before pupation a vertical tunnel and black field-crickets, etc) which feed on the to the soil surface is constructed, housing the pupa roots and underground stems of pasture plants. until eclosion (emergence). After six weeks, adult Although tree planting is generally encouraged in moths emerge, and are active in the hottest part of areas of high salinity, it is seen as a threatening sunny days between mid November and mid process on native grasslands. Planting trees as an December, depending on the aspect of the site and overstorey, alters the ecological function and warmth of the season. They survive for about two structure of the grassland. This may cause a days, unable to feed because they lack functional reduction in cover of the native grasses, mouthparts (Edwards 1991). particularly Austrodanthonia spp. Threatening processes Habitat Management Native grasslands and grassy woodlands of south The conservation of the Golden Sun Moth requires eastern Australia, have been recognised as one of that suitable habitat is retained. Protection of this Australia’s most endangered ecosystems (Lunt habitat will be beneficial for other indigenous 1991). Prior to European settlement, native species that coexist at these sites. Weeds must be grasslands and grassy woodlands covered vast reduced and the site managed to maintain a high areas of Victoria, but were one of the first areas to percentage cover of Austrodanthonia spp. Periodic be cleared for agriculture and settlement. Lunt prescriptive grazing may be required to maintain (1991) estimates that at least 99.5% have been the structure of a grassland dominated by grossly altered or destroyed. They have been Austrodanthonia spp. Gap dynamics and severely depleted through land clearance, interstitial spaces are important in the community
3 function of native grasslands and disturbances • The Salisbury Bushland Reserve site was such as prescribed grazing and fire may aid in the regularly grazed until about ten years ago. maintenance of this structure. The effects of fire Since then there has been considerable vermin is unknown. Burning could cause local extinctions and weed control on the site. The railway line and as a management option should not be extends from the Salisbury Bushland Reserve considered until further is known about the effects towards Nhill and is under the control of the fire has on the Golden Sun Moth. The percentage Public Transport Corporation and is managed cover of weeds can also increase in grasslands by regular burning. The Nhill College has when the grazing is removed. increased the cover of Austrodanthonia carphoides on the school ground, by removing The addition of fertilisers to soils provides some sugar gums and hand and direct seeding two exotic species with an advantage over native hectares. They have provided an interpretive species. Reducing the concentration of fertilisers display for visitors. The Nhill private allotment in the soil to that of native soils is imperative to has been previously grazed by stock but is the survival of native grasses. Landowners need to currently unused. be aware that when spreading fertilisers on properties neighbouring native grasslands and • The landowner of the property near Dunkeld grassy woodlands, fertiliser can be blown onto integrates the management of sheep with the these sites or can leach through the soil, altering persistence of native grasses. Grazing is their nutrient status. reduced during spring to allow native grasses to set seed. The site at Mount Piper, Broadford, is an Education • New (pers. comm.) collected a specimen in the Reserve and the Salisbury site is in a Bushland Hamilton Community Parkland, a native Reserve. These sites probably have the best grassland remnant, which is protected and prospects for the long term survival of viable managed for conservation. populations, given permanent reservation and proper management. • There is no information available concerning previous management at the Tallarook, Wider conservation issues Flowerdale and Hexham sites. An understanding of the Golden Sun Moth will • The likely distribution of the Golden Sun Moth assist in appropriate conservation management of was predicted using BIOCLIM, a computer other grassland and grassy woodland species. The generated program that produces a climatic Golden Sun Moth has value as an ‘flagship species’ profile based on information from current sites highlighting the importance of invertebrates, (Dear 1997). This indicated that the grasslands and grassy woodlands. Sponsoring of distribution of the Golden Sun Moth is likely to research helps develop expertise in invertebrate be limited to south-eastern Australia, ecology. particularly throughout the northern areas of the ACT and central Victoria. Focusing on a single species should involve management at the ecological community level, Biological research which will also benefit associated flora and fauna Investigations into the distribution, habitat of native grasslands and grassy woodlands. requirements of the Golden Sun Moth and Maintaining natural processes and native plant restoration of habitat have been undertaken by communities of native grassland and grassy Dear (1997). Individual Golden Sun moths were woodland, regardless of land tenure, will enhance collected from the ACT and two sites from Victoria their integrity and long-term viability. and the degree of genetic variation within and Previous Management Action between populations was determined (Clarke and O’Dwyer 1998). Continuing work by CSIRO and the Site Protection Zoological Parks and Gardens Board will determine • Until recently, the site at Mount Piper was on how many individuals within a population are private property and grazed by sheep. required to maintain maximum genetic variation. Fertilisers had not been added. When Education and community involvement purchased by Environment Australia (then ANCA) in 1995 the sheep were removed. Students from Nhill College have rehabilitated a Eastern Grey Kangaroos Macropus giganteus Austrodanthonia grassland within the college and Swamp Wallabies Wallabia bicolor now grounds. This work has involved studying the graze the site. The Austrodanthonia dominated ecology of the Golden Sun Moth as well as ‘grasslands’ at Mt. Piper are almost certainly an techniques to promote regeneration of artefact of clearing and subsequent grazing Austrodanthonia spp. (White pers. comm.). This project was featured as a videotape in the 1996 Student Conservation Conference ‘Habitats
4 for Wildlife’ a satellite broadcast link around Management objectives should complement Victoria coordinated by the Melbourne Zoo the reserve management plan when finalised. Education Service and resulted in a better awareness amongst some schools in rural Victoria Control weeds at known sites for the species. of the threats to the Golden Sun Moth and the 3. The site at Mt Piper is being invaded by weeds, decline of their native grassland habitat. in particular the rye grasses Lolium spp. and Yorkshire Fog Holcus lanatus. Periodic grazing Mount Piper is acknowledged as an important local would reduce the cover of these taller invasive emblem. The local conservation group, Broadford plant species. The Salisbury Bushland Reserve Environmental Action Movement (BEAM)/ Mitchell requires further action on the control of Environment Group, have shown support and weeds, particularly, Wild Oats Avena barbata interest by raising awareness and participating in and Barley Grass Hordeum spp. Spraying surveys. Signs have been erected at Mount Piper should be considered in autumn. NRE should outlining the biology of the species to promote the assist managers of the railway line site, interesting and appealing features of the Golden providing information on adequate fire Sun Moth as a means of developing support for regimes and encouraging the ceasing of conservation. Conservation notes, leaflets and cultivated fire breaks. Continuing the advice on the Golden Sun Moth, particularly for restoration of the Austrodanthonia grasslands community members in areas where the moth around the Nhill College will be encouraged. A occurs have been prepared. management agreement should be pursued Assistance from Broadford Environmental Action with the landowner of the private allotment. Movement (BEAM)/Mitchell Environment Group The site at Dunkeld is periodically grazed by and other conservation groups to support the sheep, which prevents Austrodanthonia spp. Golden Sun Moth and participate in management from being crowded. This regime allows for actions has been provided. the persistence of the habitat for the Golden Sun Moth and should not be altered. However, Intended Management Action broadleaved weeds such as Flat Weed Hypochoeris radicata and Cape Weed Survey Arctotheca calendula should be removed. This 1. NRE Parks, Flora and Fauna Division and will require ongoing liaison with the regional flora and fauna officers will landowners who are sympathetic about native implement surveys for the Golden Sun Moth. grasslands and their associated fauna. Native grasslands and grassy woodlands within the areas highlighted by BIOCLIM Interpretation and community awareness should be among the first to be investigated 4. NRE Parks, Flora and Fauna Division, regional for other possible populations. The flora and fauna officers will coordinate Tallarook/Flowerdale sites and surrounding interpretation displays at existing facilities areas and grasslands in Hexham, Dunkeld, such as Nhill College, Little Desert National Hamilton and the northern plains should be Park, Dunkeld Tourist Information Centre in included. Detailed survey work is required liaison with Parks Victoria, the college and the over successive seasons. This information will Southern Grampians Shire to improve determine which sites are viable in the long community understanding of conservation term and those which are most in need of measures required in western Victoria. NRE assistance. It will also provide information on will encourage participation of landholders yearly population fluctuations. Record known with suitable grassland and grassy woodland sites within relevant planning schemes (e.g. habitat to join the Land for Wildlife scheme by Biosites, overlays for local government areas). including Austrodanthonia native pastures as a targeted vegetation type in the program and Habitat Management monitoring such areas for the presence of the 2. NRE Parks, Flora and Fauna Division and Golden Sun Moth at the appropriate time of regional flora and fauna officers will liaise year. with land managers and landholders to ensure Other Desirable Management Action that habitat is managed appropriately. If left unmanaged these colluvial slopes will quite Biological Research quickly return to open forest. The use of the 5. Continue genetic variation analysis on all pre-existing grazing regime on the eastern side existing populations over subsequent of Mt. Piper should be investigated. Sheep generations. Refine techniques for monitoring would probably be the most appropriate extant populations. A survey technique grazers as they would prevent the further specific for the Golden Sun Moth, that encroachment of woody vegetation. considers the animal's biology and behaviour
5 should be designed. Study the ecological References effects of grazing, fire, mowing and gap ACT Government (1998) Golden Sun Moth dynamics on all sites. Habitat management, (Synemon plana): An endangered species. including research into biomass requirements, Action Plan No. 7. Environment ACT: Canberra. different methods of management Clarke, G. M. & O’Dwyer, C. (1998) Genetic Analysis (grazing/mowing/burning) and their intensity of populations of the Endangered Golden Sun and frequency need to be investigated. Give Moth, Synemon plana CSIRO Entomology consideration to the timing of control burns Canberra and the use of herbicides. Preferably not CNR (1995) Threatened Fauna in Victoria – 1995. during the flying season. Assess the effects of Department of Conservation and Natural herbicides on the Golden Sun Moth and Resources, Victoria determine toxic concentrations. It is not Common, I. F. B. (1990) Chapter 13 Superfamily known whether the larvae or pupae in the soil Castnioidea In Moths of Australia. Melbourne are directly affected by herbicides, nor have University Press, Melbourne. toxic concentrations been evaluated. Conduct Dear, C. (1996) The distribution of Synemon plana: studies to provide information on food plants. a new encounter. Vic. Entomologist 26: 26-8. It is currently assumed that the food plants Dear, C. (1997) Restoration of a native grassland are Austrodanthonia spp. This is based on the inhabited by Synemon plana (Lepidoptera). presence of tunnels between the tussocks M.Sc. Thesis, University of Melbourne: rather than on direct observations of feeding Melbourne. behaviour. Douglas, F. (1993) The conservation status, distribution and habitat requirements of Habitat Management diurnal Lepidoptera in central and western Victoria. Part 1: Family Castniidae. Department 6. Investigate the site history and previous and of Conservation and Natural Resources, intended management of the other four sites, Melbourne. Report No. 890/032. Tallarook, Flowerdale, Hexham and Hamilton Edwards, E. D. (1991) Synemon plana - a grassland Community Parkland. Monitor the growth of case history. In The ACT's native grasslands. Austrodanthonia spp. at all seven sites. The Proceeding of a workshop National Museum of early detection of a decrease in cover of Aust., Canberra. Austrodanthonia spp. would enable land Edwards, E. D. (1993) Synemon plana: An managers to implement changes in regime to endangered moth in Canberra. ANIC news 2: 7- protect the habitat. Monitor the invasion of 8 weeds at all sites and investigate techniques to Edwards, E. D. (1994) Survey of lowland grassland reduce their cover. Investigate the possibility sites in A.C.T for the Golden Sun Moth, of linking local sites. This provides potential Synemon plana. CSIRO Report to the Wildlife benefits for other species. Expand the fringe of Research Unit. ACT Parks and Conservation the habitats at all seven sites by planting local Service, Canberra. provenance Austrodanthonia spp. specific to Hadden, S. A (1998) Composition and ecology of the site the flora and fauna of remnant native grasslands of the Western Basalt Plains and Captive Colony Northern Plains of Victoria – Implications for management on private property. PhD Thesis. 7. Establish a captive colony to study the University of Ballarat: Ballarat. ecological requirements of the moth and to Harwood, T., Narain, S. & Edwards, E. D. (1995) gain a better understanding of its complex life Population monitoring of endangered moth cycle. Conduct biological studies on Synemon plana 1994-1995, York Park, Barton. population dynamics, fecundity, and length of Report to the National Capital Planning larval stages of the Golden Sun Moth. Describe Authority, Canberra. and illustrate eggs, larvae and pupae. It is Lunt, I. D. (1991) Management of remnant lowland desirable for management purposes that the grasslands and grassy woodlands for nature complete life history is understood. Captive conservation: a review. Vict. Nat. 108: 56-66. breeding may determine the sex ratio, NRE (1998) Atlas of Victorian Wildlife. (electronic fecundity, rate of mortality and length of life fauna database). Arthur Rylah Institute. cycle of the Golden Sun Moth. This may Department of Natural Resources and Environment. Heidelberg. provide an indication of population size and the potential rate of recovery of a viable SAC (1994) Final recommendation on a nomination population. A captive colony may provide for listing: Synemon plana Golden Sun Moth (Nomination No. 323). Scientific Advisory suitable stocks for translocation, and can also Committee, Flora and Fauna Guarantee. be used for interpretation activities, studies in Department of Conservation and Environment: population genetics and research in basic East Melbourne. biology.
6 Venn, D. R. (1993) Recovery plan for threatened diurnal Lepidoptera in north west Victoria. Part Compiled by Cheryl O’Dwyer Zoological Parks and 1 Castniidae and Hesperiidae. Department of Gardens Board, Sue Hadden and Andrew Arnold, Conservation and Natural Resources, South West Region, Department of Sustainability Melbourne, Victoria. and Environment.
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Flora and Fauna Guarantee Action Statements are available from the Department of Sustainability and Environment website: http://www.dse.vic.gov.au
This Action Statement was first published in 2000 and remains current. This version has been prepared for web publication. It retains the original text of the action statement, although contact information, the distribution map and the illustration may have been updated.
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